I couldn't get LambdaProbe to run on my JBoss 4.2.1GA release on my Mac. It would hit a recursive loop and then puke over a StackOverflowError.

Turns out you have to modify the code where LambdaProbe checks to see if it can bind to a particular server version. They must have renamed something in JBoss since the earlier releases, since LambdaProbe used to run without modification in the 4.0.3SP1 release.

In any event, the code change is painless, and since the project can be built with Ant and the source download comes with all the depedencies, you can have a working version in less than a minute.

See the solution on the LambdaProbe forum here.